Since a magnetic slider is used in a magnetic disk drive, it is necessary to make a HGA (Head Gimbal Assembly) which has the magnetic slider assembled to a suspension. This assembly includes the step of mechanically affixing the magnetic slider to the suspension and the step of electrically connecting the magnetic slider to the suspension. To implement this electrical connection, gold pads on the magnetic slider are joined to lead pads on the suspension mainly by using the SBB (Solder Ball Bonding). The SBB technology sets a globular chip of solder between a gold pad and lead pad and joins them together by melting the solder with a laser. Recently, this method has become the mainstream method for electrically connecting a magnetic slider to a suspension since reliable electrical connection can be obtained and almost no concern is needed about the risk of ESD (Electro-Static Discharge).
Japanese Patent Publication No. 1996-235527 (“Patent Document I”) discloses a terminal or terminal lead pad which is fabricated by plating the rear surface (opposite to the air bearing surface) of a thin film magnetic slider with Ni, NiFe, Au, Cu or other metal and depositing Au or other bonding metal thereon. The terminal or terminal lead pad is connected to a terminal conductor of the suspension spring by thermo compression bonding, ultrasonic compression bonding or the like or by using a conductive adhesive.
Japanese Patent Publication No. 1997-181125 (“Patent Document 2”) discloses a structure used to connect a semiconductor chip to a package. This structure comprises an adhesion/barrier layer adhering to the substrate of the semiconductor chip, a NiFe metal solderable layer and a lead-free solder. As the barrier layer, Cr one is cited. The NiFe metal solderable layer is designed to dissolve into the solder.
Japanese Patent Publication No. 1999-120514 (“Patent Document 3”) discloses a structure for terminals of thin film magnetic heads. A barrier layer containing Cr and an electron supply layer composed of a noble metal, below an Au film, can be formed by continuous sputtering. By welding a bonding wire to the Au film, the terminal is electrically connected to a current source provided externally.